Short Course 4 MEMS for RF/Wireless Communications Instructor: Hector De Los Santos, NanoMEMS Research LLC, USA Microelectromechanical systems (MEMS) technology is on the verge of revolutionizing RF and Microwave wireless applications [1], [2]. As the requirements of present day and future wireless systems for lower weight, volume, power consumption and cost with increased functionality, frequency of operation and component integration become more and more demanding, the potentialities of the RF MEMS arsenal to meet these requirements, by enabling new wireless components and system architectures, are becoming ever more attractive. In this course we address the fundamentals and emerging applications of this exciting technology. We begin by clearly stating the ubiquitous wireless communications problem, in particular, as it relates to the technical challenges to meet the extreme levels of appliance functionality, in the context of low power consumption, demanded by consumers in their quest for connectivity at home, while on the move or on a global basis. Next, we review those salient points in the discipline of RF circuit design, that are key to its successful practice, and which are intimately related to the successful exploitation of RF MEMS devices in circuits. In particular, the subjects of skin effect, the performance of transmission lines on thin substrates, self-resonance frequency, quality factor, moding (packaging), DC biasing, and impedance mismatch are discussed. We then undertake an in-depth examination of the arsenal of MEMS-based devices, on which RF MEMS circuit design is predicated, namely, capacitors, inductors, varactors, switches, and resonators, including pertinent information on their operation, models, and fabrication, and concluding with a discussion of a paradigm for modeling RF MEMS devices using 3-dimensional mechanical and full-wave electromagnetic tools, in the context of self-consistent mechanical and microwave design. Next, we present a sample of the many novel devices and circuits that have been enabled by exploitation of the degrees of design freedom afforded by RF MEMS fabrication techniques, in particular, reconfigurable circuit elements, such as inductors, capacitors, LC resonators, and distributed matching networks, reconfigurable circuits, such as stub-tuners, filters, oscillator tuning systems, RF front-ends, phase shifters, and reconfigurable antennas, such as, tunable dipole and tunable microstrip patch-array antennas. The course culminates with a number of case studies, which integrate all the material previously presented, as it examines perhaps the most important RF MEMS circuits, namely, phase shifters, filters, and oscillators.